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Plant Restart After Esd 2 Flare Kod


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#1 vsnlbom

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Posted 26 July 2019 - 06:28 AM

We are working on offshore oil and gas processing system. 

 

We have flare KOD with ESD 2 in case of LAHH. ESD 2 causes plant to close. As of now liquid from flare KOD is pump backed to main plant by a pump for reprocessing. My question is how to restart plant in case of ESD2 as we will not be able to pump KOD liquid back to main process. On other side it is preferable to empty KOD before plant startup.

 

Some of the solution given below

 

1) bypass ESD2 of flare KOD for startup (which i am not comfortable with) due to ESD bypass plus starting process with LAHH in flare KOD

 

2) Divert KOD liquid to separate tank (which we have), which can be diverted to main process for reprocessing after process is stabilized

 

Please let me know your views and practices normally followed



#2 Chemitofreak

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Posted 29 July 2019 - 12:56 AM

Hi,

 

First of all the Flare KOD should be designed to handle both the cases i.e. max liquid case and max vapour case.

 

The max liquid should be accommodated between the HLL and LLL i.e. the working volume.

 

The Flare KOD Pumps are sequential autostart pumps based on the liquid level i.e. one pump will start at High Liquid Level 1 and the other (standby) will start at High Liquid Level 2.

 

Even then, if you have a high level trip, then after thorough investigation the ESD Logic needs to be reset and then the plant is taken back in operation as per protocol.

 

Hope this helps you.

 

Revert in case of any query.

 

Regards,


Edited by Chemitofreak, 29 July 2019 - 12:57 AM.


#3 breizh

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Posted 29 July 2019 - 02:25 AM

Hi ,

To  me Operation should always consider the safe side to minimize the risks . No  bypass unless documented and approved

my view

Breizh 


Edited by breizh, 29 July 2019 - 07:24 AM.


#4 vsnlbom

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Posted 29 July 2019 - 04:01 AM

chemitofreak:

 

Thanks for reply.  Are you suggesting bypassing ESD logic on flare KOD to restart.My concern is in this case any additional discharge in flare KOD will be hazardous as no ESD protection is there.



#5 Chemitofreak

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Posted 29 July 2019 - 05:11 AM

vsnlbom:


 

 

 

When there is a high level in the Flare KOD, the ESD will trip all the plants relieving to that particular KOD.

 

So, there is no question of discharge from other units.



#6 vsnlbom

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Posted 29 July 2019 - 06:28 AM

chemitofreak:


 

By other unit -means can we start when KOD is LAHH and ESD-2 bypass. In remote case plant may trip again during statup resulting into more dischage to flare KOD. My view is we should first empty KOD enough to accommodate case mentioned above and for that instead of directly recycling flow to main process and tank. KOD will be emptied out intank and will be recycled afterwords.



#7 Chemitofreak

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Posted 29 July 2019 - 06:58 AM


 

 

vsnlbom: 

 

 

The Flare KOD Pumps are generally discharging to some slops tanks. By no means one is going to operate the plant with HHLL in the Flare KOD.

 

The Flare KOD shall be empty, when the plat is started.

 

Once the plant is up and running, the slops are slowly and steadily recycled in the process.






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